The introduction of frame relay in the early 1990's brought lower cost, higher bandwidth, improved reliability, and simpler management control to enterprise wide area networks (WANs) as compared to X.25 and point-to-point leased-line alternatives. Frame relay, together with single-source asynchronous transfer mode (ATM) and multiprotocol label switching (MPLS) services, still dominate the enterprise WAN market for corporate Internet traffic. A customer installs one of these networks and pays a single carrier a fee associated with the reliability and bandwidth the particular network provides. For example, a network may be advertised to provide “3 and ½ nines” (99.95%) or better reliability and have a fee based on this reliability and a cost-per-mega-bytes-per-second (Mbps). The present cost for such a network is almost as high as the fee paid back in 1998.
While performance, reliability, and predictability of a network has improved due to improvements in processor and communication architectures and implementations, these characteristics of a single network purchased from a single network provider are considered relatively low and costly. Also, load balancing is still a difficult process due to the dynamic nature of networks.